20,978 research outputs found

    3D models of lamprey corticoid receptor complexed with 11-deoxycortisol and deoxycorticosterone

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    The serum of Atlantic sea lamprey, a basal vertebrate, contains two corticosteroids, 11-deoxycortisol and deoxycorticosterone. Only 11-deoxycortisol has high affinity [Kd~3 nM] for the corticoid receptor [CR] in lamprey gill cytosol. To investigate the binding of 11-deoxycortisol to the CR, we constructed 3D models of lamprey CR complexed with 11-deoxycortisol and deoxycorticosterone. These 3D models reveal that Leu-220 and Met-299 in lamprey CR have contacts with the 17[alpha]-hydroxyl on 11-deoxycortisol. Lamprey CR is the ancestor of the mineralocorticoid receptor [MR] and glucocorticoid receptor [GR]. Unlike human MR and human GR, the 3D model of lamprey CR finds a van der Waals contact between Cys-227 in helix 3 and Met-264 in helix 5. Mutant human MR and GR containing a van der Waals contact between helix 3 and helix 5 display enhanced responses to progesterone and glucocorticoids, respectively. We propose that this interaction was present in the CR and lost during the evolution of the MR and GR, leading to changes in their response to progesterone and corticosteroids, respectively

    Lamprey watershed education and outreach

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    The Lamprey River Nomination Committee sought the assistance of the Piscataqua Region Estuaries Partnership (PREP) to complete an extensive and detailed information package to nominate the Lamprey River and its major tributaries to the NH Rivers Management and Protection Program. The nomination package was due at DES on June 1, 2010, was reviewed and accepted by the State Rivers Management Committee in September and forwarded to the Commissioner of DES. The nomination is now working through the NH legislature with hearings anticipated during the spring 2011 session. If passed, the bill should be signed by Governor Lynch in July of 2011. Assistance from PREP was essential for the completion of a major outreach effort to landowners along the rivers under consideration, communication with each town selec tboard, planning board and conservation commission, and with many partners and organizations throughout the watershe

    Update of Distribution of the Chestnut Lamprey in Arkansas

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    Most lamprey species other than sea lampreys have been poorly studied in North America. The chestnut lamprey, Ichthyomyzon castaneus, has a distribution within the Mississippi River and Hudson Bay drainage systems, and the Great Lakes. Since the text Fishes of Arkansas was published in 1988, few papers have been published to update the statewide distribution of this lamprey. We incorporated our electrofishing sampling results with gray and published literature to describe the distribution of this species in the drainage basins of the State of Arkansas. Reported are records of 250 chestnut lamprey specimens, over a 90 year period, from 47 different waterbodies in the state

    Expression of Sympathetic Nervous System Genes in Lamprey Suggests Their Recruitment for Specification of a New Vertebrate Feature

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    The sea lamprey is a basal, jawless vertebrate that possesses many neural crest derivatives, but lacks jaws and sympathetic ganglia. This raises the possibility that the factors involved in sympathetic neuron differentiation were either a gnathostome innovation or already present in lamprey, but serving different purposes. To distinguish between these possibilities, we isolated lamprey homologues of transcription factors associated with peripheral ganglion formation and examined their deployment in lamprey embryos. We further performed DiI labeling of the neural tube combined with neuronal markers to test if neural crest-derived cells migrate to and differentiate in sites colonized by sympathetic ganglia in jawed vertebrates. Consistent with previous anatomical data in adults, our results in lamprey embryos reveal that neural crest cells fail to migrate ventrally to form sympathetic ganglia, though they do form dorsal root ganglia adjacent to the neural tube. Interestingly, however, paralogs of the battery of transcription factors that mediate sympathetic neuron differentiation (dHand, Ascl1 and Phox2b) are present in the lamprey genome and expressed in various sites in the embryo, but fail to overlap in any ganglionic structures. This raises the intriguing possibility that they may have been recruited during gnathostome evolution to a new function in a neural crest derivative

    Community Land Conservation in the Coastal Watershed

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    The New Hampshire Estuaries Project (NHEP) provided a $10,000 grant to the Southeast Land Trust of New Hampshire (SELTNH) to support the hiring of a Community Land Protection Specialist to expand the region’s capacity to implement and complete conservation efforts within the coastal watershed, and specifically within the Lamprey River and Exeter River corridors. Over a period of eighteen months (January 2007 through June 30, 2008), the Community Land Protection Specialist (Specialist) worked with the Town of Brentwood, the Lamprey River Advisory Committee, and other community partners to conserve critical lands along the Exeter River, Lamprey River, and other areas of the coastal watershed. The Community Land Protection Specialist Managed all aspects of nine land conservation transactions completed during the grant period. Six projects (236 acres) are within the coastal watershed and include 1,200 feet of frontage on the Lamprey River and more than 800 feet of frontage on the Exeter River. Three other projects (189 acres) were outside of the coastal watershed. Assisted with the completion of six other land conservation transactions completed during the grant period, totaling 213 acres in the coastal watershed and 17 acres outside of the coastal watershed. The projects in the coastal watershed included 8,000 feet of frontage on the Lamprey River, 300 feet on the Taylor River, and a significant salt marsh in Rye. Conducted direct outreach (including personal letters and phone calls) in collaboration with the Lamprey River Advisory Committee to more than 45 landowners along the Lamprey River, resulting in follow-up interest among at least six landowners with ongoing conservation discussions including some appraisals and pending offers. Also hosted a land protection workshop attended by twenty-three interested landowners In collaboration with the Town of Brentwood assisted four landowners interested in conserving their land by helping them with their applications to the USDA Wetlands Reserve Program In addition, the Specialist coordinated outreach activities for targeted landowners. One estate planning and conservation options workshop was hosted in June 2007 in Epping, drawing 20 landowners. An introductory mailing and follow up calls were made to priority landowners within the Lamprey River watershed, yielding several land conservation projects that are in current discussions

    Motif analysis of amphioxus, lamprey and invertebrate estrogen receptors and amphioxus and human estrogen-related receptors: Towards a better understanding of estrogen receptor evolution

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    *Background.* The origins of steroid-dependent regulation of the vertebrate estrogen receptor (ER) are poorly understood. Genes with statistically significant sequence similarity to vertebrate ERs have been found in lamprey, a basal vertebrate, and amphioxus, a basal chordate. Motif analysis of these sequences provides an opportunity to investigate early events in the evolution of the ER.
*Results.* We used artificial intelligence-based software to construct twelve motifs specific to the estrogen-binding domain of ER[alpha] and ER[beta] in land vertebrates and teleosts. We mapped these ER-specific motifs onto the sequences of lamprey, amphioxus, invertebrate and selected vertebrate ERs and amphioxus, Ciona and human estrogen-related receptor (ERR). We find that lamprey ER contains eleven motifs common to ERs in the training set. In contrast, amphioxus ER contains only six motifs. Various invertebrate ERs contain either six or seven motifs. Unexpectedly, human and amphioxus ERRs contain nine of the twelve motifs, despite extensive sequence divergence during the descent of chordate ERs and ERRs from a common ancestor. We mapped the twelve motifs onto a multiple alignment of human, lamprey and amphioxus ERs, which depicted residues in human ER[alpha] that are known to bind estradiol. There is excellent conservation of these key residues in lamprey ER and poor conservation in amphioxus ER. Out of seventeen residues on human ER[alpha] that bind estradiol, sixteen and six are identical in lamprey and amphioxus ER, respectively. A phylogenetic tree of ERs and ERRs reveals a long branch for amphioxus ER, which is in agreement with the low sequence and motif similarity between amphioxus ER and other ERs.
*Conclusions.* There are significant differences between _B. floridae_ ER and vertebrate ERs in the steroid-binding domain as measured by motif analysis and percent of amino acids that are known to stabilize estradiol in human ER[alpha]. The absence in lamprey ER of motif 10, which maps to the C-terminus half of [alpha]-helix 9, may be important in recognition of novel estrogens, such as 15[alpha]-hydroxy-estradiol. 
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    Outreach Program to Develop And Implement Local Land Use Regulations to Protect the Remaining Undisturbed Natural Shoreland Buffers in the Towns of Candia and Deerfield, NH

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    The towns of Candia and Deerfield, New Hampshire, both situated within the Great Bay/Little Bay watershed and the Lamprey River subwatershed have agreed to participate with the Southern New Hampshire Regional Planning Commission (SNHPC) to develop and implement land use regulations to protect the remaining undisturbed natural shoreline buffers along the Lamprey and North Branch Rivers (2nd order or higher streams and tributaries) and other surface waters within these communities

    Functional Divergence of Glycoprotein Hormone Receptors

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    Two lamprey glycroprotein hormone receptors (lGpH-R I and II) highly similar with gnathostome GpH-Rs were cloned from sea lamprey testes and thyroid, respectively. Vertebrate glycoprotein protein receptors have a large extracellular domain (ED) containing a leu rich domain (LRD) linked to a rhodopsin-like transmembrane domain (TMD) through a highly divergent linker region (signal specificity domain, SSD or \u27hinge\u27 region) and a third major segment, the intracellular domain. To determine the potential roles of the different domains in the activation of the receptor following ligand-receptor binding, functional assays were performed on lGpH-R I/rat luteinizing hormone (LH)-R domain swapped chimeric receptors. These results show that the functional roles of the lamprey glycoprotein-receptor I (lGpH-R I) domains are conserved compared with its Gnathostome homologs. The ability of different glycoprotein hormones to activate chimeric lamprey/rat receptors suggests that the selectivity of the GpH-Rs in respect to their ligands is not controlled exclusively by a single domain but is the result of specific interactions between domains. We hypothesize that these interactions were refined during millions of years of co-evolution of the receptors with their cognate ligands under particular intramolecular, intermolecular and physiological constraints

    Gene regulatory networks that control the specification of neural-crest cells in the lamprey

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    The lamprey is the only basal vertebrate in which large-scale gene perturbation analyses are feasible at present. Studies on this unique animal model promise to contribute both to the understanding of the basic neural-crest gene regulatory network architecture, and evolution of the neural crest. In this review, we summarize the currently known regulatory relationships underlying formation of the vertebrate neural crest, and discuss new ways of addressing the many remaining questions using lamprey as an experimental model

    Expression of three GnRH receptors in specific tissues in male and female sea lampreys Petromyzon marinus at three distinct life stages

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    Two recently cloned gonadotropin-releasing hormone (GnRH) receptors (lamprey GnRH-R-2 and lamprey GnRH-R-3) along with lamprey (l) GnRH-R-1 were shown to share similar structural features and amino acid motifs common to other vertebrate receptors. Here we report on our findings of RNA expression of these three GnRH receptors in the three major life stages (larval, parasitic, and adult phases) of the sea lamprey, Petromyzon marinus, a basal vertebrate. For each stage, we examined the expression of messenger RNA encoding the receptors in the brain, pituitary, gonad, heart, muscle, liver, eye, intestine, kidney, skin, thyroid, gill, and endostyle by RT-PCR. In adult lampreys, the spatial expression of the three receptors in the brain and pituitary was investigated by in situ hybridization. In general, the receptors were more widely expressed in adult tissues as compared to parasitic-phase tissues and least widely expressed in the larval tissues. There were noted differences in male and female lampreys in the adult and parasitic phases for all three receptors. The data showed the presence of all three receptor transcripts in brain tissues for adult and parasitic phases and all three receptor transcripts were expressed in the adult pituitaries, but not in the parasitic pituitaries. However, in the larval phase, only lGnRH-R-1 was expressed in the larval brain and pituitary. In situ hybridization revealed that lGnRH-R-2 and -3 were expressed in the pineal tissue of adult female lampreys while lGnRH-R-1 was expressed in the pineal in adult male lampreys, all restricted to the pineal pellucida. In summary, these data provide an initial comparative analysis of expression of three lamprey GnRH receptors suggesting differential regulation within males and females at three different life/reproductive stages
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